Thursday, January 3, 2013

Van Projects - Gauges

In my quest to seek consistent performance from my westy, I have started adding additional gauges to monitor the engine.

First, I added a fuel pressure gauge and now I have an O2 sensor gauge.


I built this for less then $5, most of which was the cost of buying LEDs from Radioshack. The LED driver and voltage regulator came as free samples from TI and the rest of the parts I had in my electronics bin.

I am looking forward to mounting, perhaps inside the ash tray or below the dash. I know that it doesn't look as nice as the $25 sunpro gauge but it was one fifth the price and I got to build it. Maybe I can build a nice wood case for it to live in.

Currently it is set in Bar mode which will illuminate the LEDs from left to right. This corresponds to voltage output by the Oxygen sensor (signal wire is yellow). Green LEDs should be around a 15:1 mixture ratio which is ideal running conditions. Any LEDs to the right mean a rich running condition and any to the left mean lean running.

You may be wondering why I would want to know what the mixture ratio is, well, it can tell me a number of things about how the engine is responding to certain driving situations as well as letting me know that the sensor is actually working (I replaced this early in 2012 so it should be good).

I need to test it out on another car first to ensure that it is accurate and then install it into the van.

I might add an additional LED to this board to tell me when the throttle switch is open or closed.

FYI: I was following this site for the build http://www.scirocco.org/tech/misc/afgauge/af.html

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